Even in the past, in a paper machine which produces sheets of paper from a material, i.e., pulp, it is known that a fiber orientation of the paper produced by the paper machine has influence on dimensional stability, strength and the like of the paper. Therefore, the importance of controlling the fiber orientation profile is known as well. Patent Document 1 and Non-Patent Document 1 describe paper machines which control the fiber orientation.    [Patent Document 1] Japanese Patent Application, First Publication No. 2000-144597    [Non-Patent Document 1] “An On-Line Control System for Simultaneous Optimization of Basis Weight and Orientation Angle Profiles”, John Shakespeare, Juha Kniivila, Anneli Korpinen, Timo Johansson, (Proceeding of the First EcopaperTech, Finland, 1995, page 39-50)
In both Patent Document 1 and Non-Patent Document 1, there are descriptions of characteristics regarding stable changes of the fiber orientation when changing or adjusting an edge flow or a slice lip opening. However, these documents do not show a description from a quantitative view point with regard to changes or adjustments of the edge flow and/or slice lip opening. Therefore, the prior art has a problem in which it is difficult to control the fiber orientation with high accuracy.